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Author Topic: Color management myths and misinformation video  (Read 76551 times)

fdisilvestro

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Re: Color management myths and misinformation video
« Reply #300 on: September 03, 2014, 02:36:04 pm »

But it does have a component that can be measured and we do this all the time in science.  Back in the good old days I often used different spectrophotometers to make laboratory measurements in experiments that I was carrying out.  I also often used fluorescent molecules to tag proteins and the instrument made the measurement, not my brain (though I could see the color of the dye visually).

It is not a direct measure. You can measure wavelength, spectrum, intensity, etc and with those values determine the perceived color under a standard illuminant (e.g. D50)

bjanes

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Re: Color management myths and misinformation video
« Reply #301 on: September 03, 2014, 02:37:02 pm »

Since then, thanks almost entirely to the LuLa resident gurus (Andrew, Jeff, Michael, and Eric Chan) I have learned some of the rudiments, and the results I get with calibrated monitor, reasonable printer profiles, and soft-proofing are quite generally satisfactory.

IMHO, the list would not be complete without including Bart van der Wolf and Jim Kasson. Not only are they able to share thier vast knowledge in terms that most of us can understand, their forum etiquette is impeccable. Less collegial forum members should take note. Eric has not had much to say in these threads, and more comments from his would be most welcome.

Respectfully submitted,

Bill
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digitaldog

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Re: Color management myths and misinformation video
« Reply #302 on: September 03, 2014, 02:39:14 pm »

So here's another data point in terms of ColorThink and how it calculates gamut volume and why Slododan may want to rethink this.
I downloaded Bruce Lindbloom's Beta RGB working space. It falls within human gamut/vision while we know ProPhoto RGB doesn't.
ColorThink reports the gamut volume of ProPhoto RGB as 2,548,220. It reports Beta RGB as 1,706,750. Big, big difference. If you look at the gamut plots of both, ProPhoto does show a wider area within in the spectrum locus but lots outside it. It appears that CT doesn't take into account 'colors' that fall outside the very gamut plot CT provides to build the Gamut Volume metric (sorry for the 2D map):
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Slobodan Blagojevic

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Re: Color management myths and misinformation video
« Reply #303 on: September 03, 2014, 02:42:04 pm »

... If we're being truly practical about this, the whole question is not really important...

That I agree with.

I really could not care less if the number of colors is 16.7 million or any number above or below. All I need to know, as a practicing photographer, is that Adobe RGB (or any other wider space) CAN reproduce more vivid colors if and when I need them and if the subject has them.

The only reason I am pursuing clarification on the "more" issue, is that another practicing photographer, whose name shall not be mentioned here, was severely ridiculed for using it. While that guy got some other things wrong in an attempt to simplify it for the "normal humans," notably the rainbow clipping, he did not get the "more" thing wrong, given the context (the context being simplification).
« Last Edit: September 03, 2014, 02:54:22 pm by Slobodan Blagojevic »
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digitaldog

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Re: Color management myths and misinformation video
« Reply #304 on: September 03, 2014, 02:45:14 pm »

All I need to know, as a practicing photographer, is that Adobe RGB (or any other wider space) CAN reproduce more vivid colors if and when I need them and if the subject has them.
The only reason I am pursuing clarification on the "more" issue, is that another practicing photographer, whose name shall not be mentioned here, was severely ridiculed for using it.
The guy who stated that Adobe RGB (the wider color space) produced duller colors. Or that the two ends of each color space he was talking about (sRGB and Adobe RGB (1998)) are the same colors. And of course, that one of those color spaces had more colors than the other. He basically got just about everything wrong when talking about the two working spaces! All of that deserved ridicule.
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fdisilvestro

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Re: Color management myths and misinformation video
« Reply #305 on: September 03, 2014, 02:47:22 pm »

Isn't everything else in the universe as well?

It took only 13 pages for our resident geeks to jump off the deepest end of the philosophy pool, into solipsism.

I might not be able to explain it well, but when I say that color is not a physical property is that it cannot be quantified or measured directly like mass or size.

Eric Myrvaagnes

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Re: Color management myths and misinformation video
« Reply #306 on: September 03, 2014, 02:55:59 pm »

Thanks for the opportunity, Eric!

This is how Einstein himself explained: "Imagine one minute spent with a cute secretary... then imagine the same minute spent with your bare ass on a hot stove... which one is longer? That's relativity!"
Then Einstein fails math as well, Slobodan. He used 28 words (and 28 is greater than -- or, as you might say, more than -- 25).

But it's easier to count words than colors, which is one thing I've learned in this thread. So my own "dummy's" version of the key point of the recent debate would be something like this: "Although one may be tempted to say that a color space with a large volume has 'more' colors than one with a smaller volume, such comparisons are unreliable, for reasons that are too technical for Slobodan the average photographer to understand."

How's that?
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fdisilvestro

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Re: Color management myths and misinformation video
« Reply #307 on: September 03, 2014, 03:13:06 pm »

I was curious in finding if we could see the difference in an image where the minimum distance between any given color is 1 delta E. It turns out (If I understood correctly) that if you take an 8 bit image in a gamut that is entirely visible (sRGB, Adobe RGB) and make a round trip to Lab, then you end up with such an image.
The rationale is that working in low bit depth integers, when you convert to Lab (and the integer values of Lab are 1 delta E apart) all different RGB values that are less than 1 delta E apart will map to the same Lab value.

This is referred in Bruce Lindbloom page here

I used Bruce Lindbloom's "RGB image containing all possible colors" (from the same link, with his permission) and performed the following test:

- Assign sRGB, keep it as 8 bit
- Round trip to Lab
- examine the differences

The results: up to 100% no visible differences. It is only when going to higher magnifications (400%) that some blotchiness (sp?) can be perceived. I then substracted both images (using difference blending mode) and could see some areas with faint blotches where the Red could go up to 15.

All possible differences dissapeared when working in 16 bits, sRGB or Adobe RGB

The attached images illustrate the results using sRGB (these are screen captures since the original images are too big)

1- Original reference image
2- Round trip to Lab
3- Detail of the image in #2
4- Detail of the difference of both images (it might be difficult to perceive the blotches)

Regards

Slobodan Blagojevic

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Re: Color management myths and misinformation video
« Reply #308 on: September 03, 2014, 03:14:05 pm »

Then Einstein fails math as well, Slobodan...

Of course he did. It is a well established fact that most of his math was done by his wife, Mileva Maric, which, coincidentally, was another Serb. ;)

digitaldog

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« Last Edit: September 03, 2014, 03:23:51 pm by digitaldog »
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Jim Kasson

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Re: Color management myths and misinformation video
« Reply #310 on: September 03, 2014, 03:50:53 pm »

...the original myth I hear over and over again I was hoping to address in a video (among other myths), namely this working space has more colors than that working space. And perhaps it doesn't have to be aimed at the beginner.

Andrew, I don't think it should be part of a discussion aimed at beginners at all. While the question has utility in providing an opportunity for experts and near-experts to clarify their thinking much the way that the question "how many angels can dance on the head of a pin?" did for some theologians in the 13th century, the issues raised are, for the most part, beyond the ability of the neophyte to readily understand and not particularly useful in the day-to-day practice of color management, just as the answers to the "angels" question were to the ordinary churchgoer.

But this is your show, and all I can do is offer you friendly advice.

Jim

digitaldog

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Re: Color management myths and misinformation video
« Reply #311 on: September 03, 2014, 03:53:04 pm »

Andrew, I don't think it should be part of a discussion aimed at beginners at all.
I agree. So the question is, should the video be aimed at beginners?
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MarkM

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Re: Color management myths and misinformation video
« Reply #312 on: September 03, 2014, 04:05:12 pm »

when you convert to Lab (and the integer values of Lab are 1 delta E apart)

In LAB space L* has 100 integer values on which the 256 values from an 8bit encoding are mapped (at least that's the way the TIF spec does it). This means that an 8 bit image has steps smaller than ∆E along the L* axis, even if photoshop is only reporting the integers .
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Slobodan Blagojevic

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Re: Color management myths and misinformation video
« Reply #313 on: September 03, 2014, 04:19:15 pm »

This is more of believing what one want's to believe, not necessarily the well established facts.

http://content.time.com/time/specials/packages/article/0,28804,1936731_1936743_1936758,00.html

http://www.todayifoundout.com/index.php/2011/12/albert-einstein-did-not-fail-at-mathematics-in-school/

http://www.andyborne.com/math/downloads/myth-buster-einstein.pdf

Andrew, you are going off-topic here, but since you opened the door, I'll play. First, you apparently failed to notice a smiley at the end, indicating that I was jokingly referring to Eric's use of the phrase "failed" and the myth itself. Knowing Eric's professional background, I am sure he is fully aware of Einstein's true capabilities and was himself joking.

Now, about the phrase "well established fact" that you seem to dispute. Thanks, by the way, for the provided links, as they prove my point, rather than debunk it. From one of the referenced papers:

Quote
Back in 1905, Einstein had the biggest year of his life. He wrote, with the help of his wife, Mileva, five ground-breaking papers that, according to the Encyclopaedia Britannica "forever changed Man's view of the Universe"

And from another referenced paper:

Quote
with the help of his wife, Mileva Maric, to double check his work (she was a physicist and slightly more advanced than he in mathematics), he wrote four papers that changed the landscape of Physics:

Jim Kasson

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Re: Color management myths and misinformation video
« Reply #314 on: September 03, 2014, 04:29:22 pm »

If you look at the gamut plots of both, ProPhoto does show a wider area within in the spectrum locus but lots outside it. It appears that CT doesn't take into account 'colors' that fall outside the very gamut plot CT provides to build the Gamut Volume metric (sorry for the 2D map):


uv! Thank you, Andrew.

I wonder what the kinks in the PP lines are about...

Jim
« Last Edit: September 03, 2014, 04:31:52 pm by Jim Kasson »
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Rhossydd

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Re: Color management myths and misinformation video
« Reply #315 on: September 03, 2014, 05:04:42 pm »

I agree. So the question is, should the video be aimed at beginners?
Well what you've been discussing in tedious, pedantic, solipsistic detail over the last eight pages is, to say the very least, so esoteric only experts need watch.

There seems to be a huge resistance here to simplify and state the obvious in accessible terms.
Why was I only the only person that, correctly, answered Gary Fong's challenge to say whether a print from an Adobe RGB file would be better than from an sRGB file of the same subject ? Yes, assuming there was colour in the subject that wasn't in sRGB. Just arguing about the pedantic definitions just made everyone look as bad he expected(hoped?).

You've all been arguing about the statement "Has Adobe RGB got more colours than sRGB?"
why ? Just think of it as a typing error and take the S out.
You get "AdobeRGB has more colour than sRGB" which is an easily understood way of explaining why we use wide gamut colourspaces.

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fdisilvestro

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Re: Color management myths and misinformation video
« Reply #316 on: September 03, 2014, 05:18:00 pm »

In LAB space L* has 100 integer values on which the 256 values from an 8bit encoding are mapped (at least that's the way the TIF spec does it). This means that an 8 bit image has steps smaller than ∆E along the L* axis, even if photoshop is only reporting the integers .

Thanks for pointing that out, so the result is not precisely RGB vales 1 delta E apart. In any case, and following Bruce's website, going from 16 million different RGB values to just above 2 millions, resulted in an image almost indistinguishable from the original

fdisilvestro

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Re: Color management myths and misinformation video
« Reply #317 on: September 03, 2014, 05:21:41 pm »


Why was I only the only person that, correctly, answered Gary Fong's challenge to say whether a print from an Adobe RGB file would be better than from an sRGB file of the same subject ? Yes, assuming there was colour in the subject that wasn't in sRGB. Just arguing about the pedantic definitions just made everyone look as bad he expected(hoped?).


That was one of the possible outcomes, maybe the most likely, but not the only one. He said what he was going to do but not how.

MarkM

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Re: Color management myths and misinformation video
« Reply #318 on: September 03, 2014, 05:23:51 pm »

Why was I only the only person that, correctly, answered Gary Fong's challenge to say whether a print from an Adobe RGB file would be better than from an sRGB file of the same subject ?

I don't think we had a reason to believe he wasn't just going to print unmanaged color from an AdobeRGB file to a printer expecting sRGB data. The reason many of thought this was a possibility was that his whole video treated the subject of AdobeRGB as if that was how people normally handled ARGB data. His whole premise was that you get "dull colors" from ARGB — the only way this happens is when you interpret it incorrectly i.e. assign sRGB or similar to the data. Since he wouldn't (or could't) explain how he was going to manage colors, nobody knew what he was going to do. It was 50-50.  I would say you were correct that an AdobeRGB files can make a better print, but only got lucky that his test agreed with you.

There seems to be a huge resistance here to simplify and state the obvious in accessible terms.

Any time you get a room full of people who love and know a lot about a subject you will find them discussing the edge cases. I suspect almost everyone contributing to this topic is capable of stating this in accessible terms. But we also know that to do so leaves out some, arguably important, precision in the answer. When to be imprecise but accessible and when to ask the reader to think about the problem a little more deeply in the name of grasping the nuance is a difficult choice. The Einstein example is a great lesson: we all understand the secretary vs. the hot stove, but try to use that "understanding" of relativity to predict the red shift of a distant star and you will soon learn that you don't really understand anything about relativity in practice.

I personally think it's smart of Andrew to work through some of the problems of his topic in a space like this before trying to condense it to something more accessible.
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digitaldog

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Re: Color management myths and misinformation video
« Reply #319 on: September 03, 2014, 05:36:28 pm »

Well what you've been discussing in tedious, pedantic, solipsistic detail over the last eight pages is, to say the very least, so esoteric only experts need watch.
Well that's one opinion and you are of course entitled to it.
Quote
There seems to be a huge resistance here to simplify and state the obvious in accessible terms.
I don't agree any of it is obvious. Or tedious, pedantic, solipsistic, just the opposite. I believe I know a little bit about this subject and I've learned a lot over the last few pages. As the original poster, I'm happy I posed the questions I did and appreciate the replies of those who also found the subject worth discussing even debating.

Of course if anyone feels the pages are tedious, pedantic, solipsistic or off topic, they are free to move on, turn off notifications. This isn't class where you are required to attend or get a bad grade.
Quote
Why was I only the only person that, correctly, answered Gary Fong's challenge to say whether a print from an Adobe RGB file would be better than from an sRGB file of the same subject ?
I can only speak for myself. I refused to take Gary's bait based on his absolutely silly described testing methodology.
Quote
Just arguing about the pedantic definitions just made everyone look as bad he expected(hoped?).
Again, that's your opinion, I frankly found it quite different. The person who continued to look sillly was Gary (and anyone defending him) based on his flat earth color theories.
Quote
You've all been arguing about the statement "Has Adobe RGB got more colours than sRGB?"why ? Just think of it as a typing error and take the S out.
Gary doesn't deserve that honor! It's a statement that you can find all over the internet. Much like "All displays are 72dpi, dymamic range is the same as bit depth, all output should have a resolution of 300DPI etc.
Quote
You get "AdobeRGB has more colour than sRGB" which is an easily understood way of explaining why we use wide gamut colourspaces.
Adobe RGB doesn't have more color than sRGB. It has different colors. It can produce a more saturated color. Of like Gary, you can mangle how to use that working space and get duller colors.
« Last Edit: September 03, 2014, 05:58:48 pm by digitaldog »
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